2.3 Results
2.3.6 Farmers’ perceptions of symptoms of bean root rot
Bean root rots were mainly observed before flowering, that is, at the 3-4 leaf stage.
Farmers recognized BRR based on several symptoms, which included yellowing, drying of the whole plant or roots, wilting, water-soaked roots, stunted growth, brittle roots, small leaves, poor root development, flower drop, weak and reduced root mass, roots, and poor pod set (Table 2.7). Of the symptoms mentioned, plant yellowing was the main symptom farmers associated with BRR, followed by drying-up of the whole plant (Table 2.7). Root rot symptoms were said to be most severe where the soil was considered infertile. In several cases, this occurred in patches in bean fields, with some plants having a yellow colour and others having a healthy green colour. Symptoms would gradually spread to cover the whole field, or in other cases, infected plants would die while others would survive to give some yield. In south-western Uganda, farmers recognized most BRR symptoms on fields located on hillsides, where the soils were shallow, and not in the valleys, where the soil was deep.
Table 2.7. Pooled percentage of respondents over four districts (Kabale, Kisoro, Mbale, and Sironko) in Uganda mentioning different symptoms of baen root rot (2005).
Symptom % Respondents
Yellowing 76.8
Drying-up of plant 63.2
Drying of roots 27.4
Wilting 26.3
Water-soaked stem and rots/rotten roots and stem 14.7
Stunted growth 13.7
Drop of root hairs 11.6
Leaves shrinking 7.4
Poor root development 5.3
Flower drop and poor flowering 3.2
Few and weak roots 4.2
Lack of pods 2.1
A large percentage of farmers in south-western Uganda associated BRR occurrence with excessive rainfall, and could not conclusively tell the number of times the epidemic occurred in a year. However, a few farmers observed the disease symptoms once a year, usually in the season that received high rainfall, while others, especially in eastern Uganda, observed root rot epidemics every season. A few claimed that root rot
epidemics were unpredictable and occurred unexpectedly, while others associated them with seasons when it was dry (Table 2.8).
Table 2.8. Percentage of farmers mentioning the frequency of occurrence of bean root rot epidemics in four didtricts of Uganda (2005).
% Respondents Frequency
Kabale Kisoro Mbale Sironko
Once a year 23.3 30.0 40.0 43.3
Every season 3.3 2.0 28.6 26.7
Rare 3.3 0.0 0.0 0.0
Unpredictable 13.3 10.0 13.3 20.0
Whenever it is wet (too much
rain) 56.8 45.5 0.0 0.0
Whenever it is dry 0.0 0.0 2.9 0.0
2.3.7 Farmers’ perceptions of the factors causing bean root rot
The factors farmers associated with the cause of BRR were similar to the ones mentioned for bean diseases as a whole (Section 2.3.3). However, in the case of BRR, excessive rainfall was considered the major predisposing factor, while poor soils were considered most important for all diseases (Section 2.3.3). In addition, drought was considered a major factor in predisposing beans to root rot, especially in eastern Uganda (Table 2.9), while poor soil was ranked as the second and third most important factor that predisposes beans to root rot in south-western and eastern Uganda, respectively. A few farmers said they did not know what caused root rots in beans.
Other factors mentioned included poor soil drainage, shallow soils caused by soil erosion, because most bean fields are on hill slopes in south-western Uganda and over- cultivation of soil caused by land fragmentation, especially in south-western Uganda. A few farmers, especially in Kabale, associated BRR with witchcraft and cultural rituals were said to be performed to control it in case of an epidemic. For example, one respondent claimed that when the disease occurred, a few of the dead and sick plants are uprooted, placed on a boat with all family members and rowed over Lake Bunyonyi, while chanting “Kuka Runiga”, meaning “root rot disappear”, to their gods.
Table 2.9. Percentage of farmers in four districts ogf Uganda (Kabale, Kisoro, Mbale and Sironko) mentioning different factors that influence the occurrence and severity of bean root rot (2005).
% Respondents Cause
Kabale Kisoro Mbale Sironko
Excessive rain 93.3 89.5 40.0 50.0
Drought 10.0 15.0 45.7 46.7
Poor soil 20.0 26.5 20.0 6.7
Lack of crop rotation 0.0 0.0 8.6 6.7
Water stagnation 20.0 5.0 2.9 10.0
Planting under trees 0.0 0.0 2.9 3.3
Weeds 0.0 5.0 0.0 6.7
Intercropping 0.0 0.0 2.9 0.0
Lack of resistant varieties 0.0 3.5 5.7 0.0
Insects in soil 0.0 0.0 11.4 0.0
Pests 0.0 0.0 20.0 0.0
Witchcraft 3.3 0.0 0.0 0.0
Don’t know 3.3 0.0 5.7 10.0
2.3.8 Farmers’ practices in combating bean root rots
Most farmers, especially in Kabale and Mbale, did nothing once the disease occurred.
However, roguing was the main control practice used, especially in eastern Uganda, while adding farm yard manure was the major control practice for BRR in south-western Uganda. Other control measures included constructing water channels, hand irrigation during drought periods, planting bean variety mixtures, applying ash around infected plants, and terracing. Hilling up and planting mature seed were mainly mentioned in south-western Uganda, while weeding was mentioned in Mbale and Kabale only (Table 2.10). Other control measures mentioned during the FGDs included, addition of inorganic fertilizers (very few are able to afford this), spraying with chemicals (very few farmers spray against root rots but spray mainly against insect pests), timely planting, good quality seed, soil conservation using drainage trenches, fallowing, crop rotation, intercropping, planting improved varieties (resistant varieties, although in most cases these have succumbed to the disease), spreading ash on infected plants, weeding, ridging, roguing, and burying infected plants.
Table 2.10. Percentage of farmers mentioning different control measures for bean root rots in four districts of Uganda (2005).
% Respondents Control measure
Kabale Kisoro Mbale Sironko
Nothing 43.3 45.0 31.4 13.3
Farmyard manure 26.7 32.4 0.0 3.3
Roguing 10.0 12.5 28.6 53.3
Crop rotation 16.7 9.7 8.6 8.6 Intercropping 0.0 0.0 0.0. 3.3 Addition of fertilizer 3.3 5.6 0.0 0.0 Improved varieties 3.3 0.0 2.9 0.0
Fallowing 0.0 0.0 2.9 0.0
Ash 0.0 0.0 2.9 0.0
Weeding 3.3 0.0 11.4 0.0
Traditional methods 10.0 0.0 0.0 0.0 Hilling up 3.3 4.8 0.0 0.0 Planting mature seed 6.6 6.7 0.0 0.0
2.3.9 Farmers’ perceptions of the characteristics of a desirable bean variety
Farmers consider several factors in choosing bean varieties to grow, with yield being the most important factor, followed by early maturity, marketability, disease resistance, taste and drought tolerance (Figure 2.7). Other factors considered include bush growth habit (mentioned only in eastern Uganda, as both bush type and climbing types are popular in south-western Uganda), short cooking duration, seed size, especially large seed-sized varieties, light-coloured beans, that is, brown, red or white, storability and resistance to excessive rainfall.
0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0
High yielding Early m
aturing Mar
ketability
Disease resistant Drought res
istant Taste
Bush type
Short cooking duration Big seed size
Colour Storability
Res istance to ex
cessive rain
Characteristics
% Respondents
Fig. 2.7. Pooled percentage over four districts (Kabale, Kisoro, Mbale and Sironko) of what bean farmers perceive to be the characteristics of a good bean variety.
2.3.10 Farmers’ bean seed size preferences and reasons for preferences
Generally, large-seeded bean varieties were the most preferred in both eastern and south-western Uganda (Figure 2.8), although the percentage was greater in eastern Uganda. The percentage of farmers preferring small-seed varieties was greater in south- western Uganda. This could probably be related to the reports of farmers slowly shifting to preferring the small-seeded varieties because of their resistance to BRR; as BRRs were the major disease in the south-western region, this seems the probable reason.
0 10 20 30 40 50 60 70 80 90 100
South-w estern Eastern Region
% Respondents
Large Small Both
Fig. 2.8. Bean seed size preferred in two regions in Uganda (2005).
Farmers mentioned various reasons as to why they preferred the large-seeded varieties (Figure 2.9). Reasons ranged from the ability of large-seeded beans to give higher yields compared to the smaller seeded varieties, and their preference on the market, to the fact they swell when cooked, meaning that only small amounts are necessary for a meal.
Other reasons included a better taste/texture when eaten and a good appearance, especially for farmers who market the beans (Figure 2.9). Some farmers mentioned that large-seeded varieties were less vulnerable to destruction by bruchids in storage. It was also mentioned during the FGDs that the leaves and stems of large-seeded varieties could be eaten, unlike the small-seeded varieties. Also, it was mentioned that the crop of the large-seeded varieties was uniform in its growth compared to small-seeded varieties, which usually mature at different times.
0 10 20 30 40 50 60
High yielding M arketability Good taste/texture
Good appearance
Swelling Storability Edible leaves and stems
Uniformity
Reasons
% Respondents
Fig. 2.9. Pooled percentages over four districts (Kabale, Kisoro, Mbale, and Sironko) of respondents giving various reasons for preferring large-seeded bean varieties.
The farmers who preferred the small-seeded bean varieties based their preferences on the ability to resist pests and diseases and to thrive under harsh environments such as excessive rainfall, drought, and mist, when compared to the large-seeded varieties (Figure 2.10).
0 5 10 15 20 25 30 35 40 45
South-western Eastern Region
% Respondents
Marketability
Resistance to harsh environment Resistance to pests and diseases High-yielding
Fig. 2.10. Reasons for preferring small-seeded bean varieties in two bean growing regions in Uganda (2005).
Yield was also mentioned because most of the small-seeded varieties are very high-yielding and hence ensured food security. Marketability was the least mentioned factor for small- seeded bean preferences, probably because these varieties are not as marketable as the large seed types. However, most farmers grew small-seeded varieties for consumption and rarely, if at all, marketed them (Figure 2.10).
2.3.11 Farmers’ bean seed colour preferences
Generally, farmers based their preferences of bean seed colour on the colour of soup produced after cooking, marketability, taste, storability, yield, and appearance (Figure 2.11).
Light-coloured varieties such as red, red mottled, brown, yellow, and white in comparison to darker-coloured varieties such as dark brown, black, and purple, were the most preferred bean seed types due to the colour of the soup produced after cooking. The red mottled varieties were most preferred, especially in eastern Uganda, followed by brown coloured ones, especially in Kabale. Other types grown included mixtures, mainly in Kabale, black in Mbale, black and white mottled in Kabale and Sironko, white in Mbale and pink in Sironko. A few farmers, mainly those that grew for home consumption, had no colour preference, and grew whatever was available.
0 10 20 30 40 50 60 70
South-w estern Eastern Region
% Respondents
Colour of soup Marketability Good taste Appearance High yielding Storability
Fig. 2.11. Percentage of farmers giving specific reasons for preferring particular bean seed colour in two bean growing regions in Uganda (2005).
2.3.12 Farmers’ perceptions of the relationship between resistance to bean root rot, seed size, and growth habit of bean varieties being grown
As regards resistance to BRR, a large percentage of farmers made some observations on which varieties seemed to resist root rot. In south-western Uganda, 50% of the respondents had observed resistant varieties, while 40-49% had done so in eastern Uganda. In south- western Uganda, resistance to root rot was mainly associated with the small-seeded varieties, that is, 58% in Kabale and 65% in Kisoro while a few related resistance to both the small-seeded and larg-seeded varieties, that is, 29% in Kabale and 14% in Kisoro (Figure 2.12a and b). However, in eastern Uganda, root rot resistance was more associated with large seed size, that is, 33% in Sironko and 45% in Mbale (Figure 2.8 c and d). Some farmers (17% in Sironko and 25% in Mbale) said small seed sized varieties were resistant, while others (17% in Mbale and 25% in Sioronko) mentioned that both small- and large- seeded varieties were resistant. In all the districts, 11% to 25% of the farmers did not associate root rot resistance with seed size (Figure 2.12).
a.
Kabale district
0 10 20 30 40 50 60 70
Large Small Both small and large
No relationship Seed size
% Respondents
b.
Kisoro district
0 10 20 30 40 50 60 70
Large Small Both small and large
No relationship Seed size
% Respondents
c.
Sironko district
0 5 10 15 20 25 30 35
Large Small Both small and large
No relationship Seed size
% Respondents
d.
Mbale district
0.0 10.0 20.0 30.0 40.0 50.0
Large Small Both small and large
No relationship Seed size
% Respondents
Fig. 2.12. Percentage of farmers in a) Kabale, b) Kisoro, c) Sironko, and d) Mbale districts in Ugand relating different seed sizes to resistance to root rot (2005).
A few farmers, associated resistance to BRR with the type of growth habit of the bean varieties. In south-western Uganda, 45-60% of the respondents who observed resistance to root rot associated the resistance with climbing growth habit, while the rest did not perceive any relationship. In eastern Uganda, less than 5% of the respondents who observed resistance to root rot associated the resistance with climbing growth habit, while the rest said there was no relationship between growth habit and resistance to root rot.
2.3.13 Incidence and severity of bean root rot in farmers’ fields
Based on the visual symptoms in the bean fields visited as a whole, and on the hypocotyl and roots of ten plants sampled per field, there were no significant differences (P≤0.05) between the districts and villages regarding incidence and severity of bean root roots.
Generally the incidence of root rots was highest in Kabale and Kisoro (see Figure 2.13) where, in some villages, such as Ryakarimira and Rutare, all the bean fields visited had root rot symptoms. This was followed by Sironko and lastly Mbale which did not have such high BRR incidences in the bean fields visited (Table 2.11).
Fig. 2.13. A farmers’ bean field in Kisoro showing yellowing due to bean root rot.
Bean root rot severities ranged between 10% and 34% based on the observations of root rot symptoms on the plant hypocotyl and root tissue (Table 2.11).
Table 2.11. Incidence and severity of root rots in bean fields in Kabale, Kisoro, Mbale and Sironko districts of Uganda (2005).
District Village Incidence (%) Severity (%)
Kabale Ryakarimira 100 33.8
Ntarangama 60 19.5
Kisoro Nyarusiza 80 27.9
Rutare 100 34.1
Mbale Makhai 40 10.0
Namwaro 50 19.8
Sironko Bunywaka 50 20.2
Bwikhonge 80 22.2
Mean 70.0 23.4
S.e.d. (P ≤ 0.05) 6.7
CV% 42.1
2.3.14 Marketing of beans in south-western and eastern Uganda
Very few farmers, that is, 16% in south-western and 20% in eastern Uganda, produce beans for consumption only while the majority produce for both consumption and sale (Table 2.12).
Table 2.12. Percentage of farmers who sell beans in four districts of Uganda (2005).
% Respondents Districts
Sell to neighbours and
traders from home Sell in markets Do not sell
Kabale 53.3 73.3 16.7
Kisoro 34.2 76.8 15.0
Mbale 68.6 42.9 20.0
Sironko 90.0 60.0 0.0
Mean 61.5 63.3 12.9
In eastern Uganda, a large percentage of farmers sell their bean produce from their homesteads as traders can easily access the homes, while in south-western Uganda farmers have to carry their produce to the markets as very few traders are able to get to the homesteads due to the hilly terrain. The bean farmers in eastern Uganda also enjoy a ready
market with the bordering country of Kenya. Bean production is thus more of a business for them, unlike their counterparts in south-western Uganda, whose market in Rwanda and the DRC is not so lucrative. Generally bean farmers, especially in south-western Uganda, complained of having poor returns for their produce because of the low prices of beans caused by the lack of a formal marketing system. In most cases, the farmers have no say in price determination and accept whatever the traders have to offer. K132 was reported to earn the highest prices of 150-700Ushs kg-1 in Sironko and Mbale, 250-600Ushs kg-1 in
Kabale and Kisoro; followed by Kanyebwa at 150-600Ushs kg-1 in Sironko, 150-400Ushs kg-1 in Mbale, 500Ushskg-1in Kabale; and finally, K20 at a price of 100-
370Ushs kg-1 in Sironko, 150-400Ushs kg-1in Mbale, and 150-450Ushs kg-1in Kabale.
2.4 Discussion
The PRA helped in elucidating farmers’ perceptions of various issues related to BRR that will guide future breeding programmes by solving “real problems” rather than solving
“perceived problems” that may not be the actual problems. This study was carried out mainly to determine the need for new varieties with improved resistance to BRR, which is one of a complex of pathogens causing BRR. The study assessed farmers’ perceptions of BRR, management of bean diseases and their perceptions on the causes of bean root and how they relate BRR to the types of bean varieties being grown. It also assessed the level of BRR infection on farmers’ fields. The major characteristics of beans that farmers consider when adopting a new bean variety were also identified. The data was obtained from a formal survey of 120 households/respondents and focus group discussions, with over 240 respondents from four districts in the highland regions of Uganda. Additional data were obtained from secondary sources such as the Ministry of Agriculture, NARO and NGOs involved in bean production.
From the PRA, bean root rots were recognised by farmers as the major constraint to bean production, especially in south-western Uganda. Resistance to BRR, as well as seed quality traits, especially large seed size and light seed colour, were the major traits that needed intervention by breeders. Similarly in Malawi, root rot tolerance and seed quality were considered top priority for genetic improvement (Snapp et al., 2006). However, BCMV was considered the major disease affecting bean production in eastern Uganda.
The study showed that, 40%-100% of the bean fields visited were infected with root rot.
The disease was easily recognized by the farmers in Kabale and Kisoro districts in the south-western highlands, where it was associated with low bean production. In Kabale it was referred to as “Kiniga” and in Kisoro as “Kirusuka”. The factors which farmers associated with the cause of BRR were similar to the ones mentioned for all other bean diseases, implying that farmers often recognize diseases as a whole, that is, they tend to consider the general appearance of the whole bean plant and not specific diseases attacking a particular plant part. This is important for researchers to note, as they usually target specific diseases and may be misled by the farmers’ responses. Hence, there is a need to probe at some depth to get specific details of the pathogen one is investigating.
Excessive rain, drought and poor soil fertility were the major factors predisposing beans to root rot. Many other factors mentioned as causes of BRR, such as low soil depth/shallow soils due to soil erosion, insects/organisms in the soil, lack of crop rotation, planting under trees, lack of intercropping, lack of fertilizer and farmyard manure, and over-cultivation were all soil-related. This implies that poor soil fertility and soil sanitation were the major causes of BRR. However, even though farmers were able to observe the causes of root rot they were not able to explain the reasons for it. For instance, farmers who associated BRR with excessive rain could not explain why root rot was also observed in drought periods.
Bean root rots are associated with the intensification of agriculture, which has been a result of the increasing human population. The high population characteristic of the highland regions has led to land fragmentation and hence a decline in soil fertility. This has created a scenario where there is an imbalance between the beneficial and disease causing organisms in the soil, and hence an increase in root rot pathogen inoculum levels (Buruchara and Rusuku, 1992; Pyndji, 1996).
It was evident that farmers did not have a clear understanding of the causal organism of BRR. Even though some mentioned insects in the soil, it was probable that they were referring to bean fly or an actual insect, and not a pathogen. The idea of a soil-borne pathogen was poorly understood.